Hardin -- U.S. County in Ohio Population (2000): 31945 Housing Units (2000): 12907 Land area (2000): 470.290597 sq. miles (1218.047002 sq. km) Water area (2000): 0.245256 sq. miles (0.635209 sq. km) Total area (2000): 470.535853 sq. miles (1218.682211 sq. km) Located within: Ohio (OH), FIPS 39 Location: 40.666602 N, 83.648242 W Headwords: Hardin Hardin, OH Hardin County Hardin County, OH